Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a no...Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.展开更多
Nitrogenous heterocyclic compounds are key pollutants in coking wastewater; however, the functional potential of microbial communities for biodegradation of such contaminants during biological treatment is still elusi...Nitrogenous heterocyclic compounds are key pollutants in coking wastewater; however, the functional potential of microbial communities for biodegradation of such contaminants during biological treatment is still elusive. Herein, a high throughput functional gene array（Geo Chip 5.0）in combination with Illumina Hi Seq2500 sequencing was used to compare and characterize the microbial community functional structure in a long run（500 days） bench scale bioreactor treating coking wastewater, with a control system treating synthetic wastewater. Despite the inhibitory toxic pollutants, Geo Chip 5.0 detected almost all key functional gene（average61,940 genes） categories in the coking wastewater sludge. With higher abundance, aromatic ring cleavage dioxygenase genes including multi ring1,2 diox; one ring2,3 diox; catechol represented significant functional potential for degradation of aromatic pollutants which was further confirmed by Illumina Hi Seq2500 analysis results. Response ratio analysis revealed that three nitrogenous compound degrading genes-nbz A（nitro-aromatics）, tdn B（aniline）, and scn ABC（thiocyanate） were unique for coking wastewater treatment, which might be strong cause to increase ammonia level during the aerobic process. Additionally, Hi Seq2500 elucidated carbozole and isoquinoline degradation genes in the system. These findings expanded our understanding on functional potential of microbial communities to remove organic nitrogenous pollutants;hence it will be useful in optimization strategies for biological treatment of coking wastewater.展开更多
Reaction of (MeC 5H 4) 3Ln with HOCH 2CH 2NMe 2 in tetrahydrofuran(THF) gives the new complexes [(MeC 5H 4) 2Ln(μ OCH 2CH 2NMe 2)] 2 (Ln=Sm, Y, Nd) with nitrogen functionalized μ alkoxide ligand. The ...Reaction of (MeC 5H 4) 3Ln with HOCH 2CH 2NMe 2 in tetrahydrofuran(THF) gives the new complexes [(MeC 5H 4) 2Ln(μ OCH 2CH 2NMe 2)] 2 (Ln=Sm, Y, Nd) with nitrogen functionalized μ alkoxide ligand. The complexes were characterized by elemental analysis and IR, and [(MeC 5H 4) 2Sm(μ OCH 2CH 2NMe 2)] 2 was structurally characterized by the X ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm-N bonds via intramolecular coordination of OCH 2CH 2NMe 2. The coordination number of the central metal Sm is nine. The title complexes show good catalytic activity for ring opening polymerization of ε caprolactone.展开更多
Background The forest-steppe ecotone,a critical transition zone sensitive to global change,faces increasing nitrogen deposition.However,the interplay between nitrogen conversion processes and soil enzyme activity rema...Background The forest-steppe ecotone,a critical transition zone sensitive to global change,faces increasing nitrogen deposition.However,the interplay between nitrogen conversion processes and soil enzyme activity remains unclear.We investigated the effects of nitrogen addition on plant nutrient dynamics,microbial functional genes,and enzyme activity in northwest Liaoning,China.Results Nitrogen addition significantly increased leaf nitrogen content in Potentilla tanacetifolia(peak under N40)and Artemisia frigida(peak under N40),while Lespedeza daurica showed a non-linear response(peak under N20).Phosphorus content remained unaffected across species.Soil enzyme activities(urease,nitrate reductase,dehydrogenase)increased with nitrogen input,with protease activity rising proportionally to nitrogen addition rate.Functional genes(nirK,nifH,AOB-amoA)exhibited dynamic responses:nirK abundance peaked under N40,nifH under N10,and AOB-amoA increased with nitrogen input.Structural equation modeling revealed that nirK gene abundance positively influenced enzyme activity(λ=0.512),while nifH negatively correlated with leaf N/P ratios(λ=-0.606).Soil protease activity directly drove leaf N/P ratios(λ=0.734).Conclusions Nitrogen addition enhances plant nitrogen uptake and enzyme-driven mineralization,but speciesspecific responses highlight ecological trade-offs.Soil pH and protease activity are pivotal in mediating nitrogen conversion and plant nutrient stoichiometry.These findings underscore the need to integrate microbial and enzymatic dynamics into nutrient management strategies for ecotones under nitrogen enrichment.展开更多
Freshwater salinization is receiving increasing global attention due to its profound influence on nitrogen cycling in aquatic ecosystems and the accessibility of water resources.However,a comprehensive understanding o...Freshwater salinization is receiving increasing global attention due to its profound influence on nitrogen cycling in aquatic ecosystems and the accessibility of water resources.However,a comprehensive understanding of the changes in river salinization and the impacts of salinity on nitrogen cycling in arid and semi-arid regions of China is currently lacking.A meta-analysis was first conducted based on previous investigations and found an intensification in river salinization that altered hydrochemical characteristics.To further analyze the impact of salinity on nitrogen metabolism processes,we evaluated rivers with long-term salinity gradients based on in situ observations.The genes and enzymes that were inhibited generally by salinity,especially those involved in nitrogen fixation and nitrification,showed low abundances in three salinity levels.The abundance of genes and enzymes with denitrification and dissimilatory nitrate reduction to ammonium functions still maintained a high proportion,especially for denitrification genes/enzymes that were enriched under medium salinity.Denitrifying bacteria exhibited various relationships with salinity,while dissimilatory nitrate reduction to ammonium bacterium(such as Hydrogenophaga and Curvibacter carrying nirB)were more inhibited by salinity,indicating that diverse denitrifying bacteria could be used to regulate nitrogen concentration.Most genera exhibited symbiotic and mutual relationships,and the highest proportion of significant positive correlations of abundant genera was found under medium salinity.This study emphasizes the role of river salinity on environment characteristics and nitrogen transformation rules,and our results are useful for improving the availability of river water resources in arid and semi-arid regions.展开更多
To improve nitrogen removal performance of wastewater treatment plants （WWTPs）, it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study character...To improve nitrogen removal performance of wastewater treatment plants （WWTPs）, it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study characterized the quantity and diversity of nitrogen cycling genes in various processes of municipal WWTPs by employing two molecular-based methods：most probable number-polymerase chain reaction （MPN-PCR） and DNA microarray. MPN-PCR analysis revealed that gene quantities were not statistically different among processes, suggesting that conventional actwated sludge processes （CAS） are similar to nitrogen removal processes in their ability to retain an adequate population of nitrogen cycling microorganisms. Furthermore, most processes in the WWTPs that were researched shared a pattern：the nitS and the bacterial amoA genes were more abundant than the nirK and archaeal amoA genes, respectivelv. DNA microarray analysis revealed that several kinds of nitrification and denitrification genes were detected in both CAS and anaerobic-oxic processes （AO）, whereas limited genes were detected in nitrogen removal processes. Results of this study suggest that CAS maintains a diverse community of nitrogen cycling microorganisms; moreover, the microbial communities in nitrogen removal processes may be specific.展开更多
Direct sewage discharge may enhance soil nitrous oxide(N_(2)O)emissions,worsening the greenhouse effect.However,the effects of sewage discharge into bogs on N_(2)O flux,drivers and influencing mechanisms remain unclea...Direct sewage discharge may enhance soil nitrous oxide(N_(2)O)emissions,worsening the greenhouse effect.However,the effects of sewage discharge into bogs on N_(2)O flux,drivers and influencing mechanisms remain unclear.Additionally,investigating the impact of reclaimed water on N_(2)O flux is important for bog replenishment and water shortage alleviation.This study simulated sewage from different sources into a bog and analyzed N_(2)O fluxes,soil(organic carbon,total nitrogen,ammonium nitrogen,nitrate nitrogen,total phosphorus,available phosphorus,pH and electrical conductivity),plant(species richness and biomass)and microorganisms(ammonia-oxidizing archaea,napA,nirS,nirK and nosZ genes).Results showed that the reclaimed water did not significantly change N_(2)O flux,while 50%tap water mixed with 50%domestic sewage and domestic sewage significantly increased the N_(2)O flux.Among soil factors,available nitrogen and pH were key in influencing N_(2)O flux.Among plant parameters,species richness was the primary factor affecting N_(2)O flux.Nitrogen transformation functional genes contributed the most to the increase in the N_(2)O fluxes,with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N_(2)O emissions.Therefore,domestic sewage should be considered,as it significantly increases N_(2)O emissions by affecting the soil,plants and microorganisms,thereby increasing the global warming potential.This study’s findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.展开更多
基金financially supported by the Research Program from Korea Institute of Industrial Technology(EM220011)the Technology Innovation Program(20020229,Development of technology for manufacturing catalysts and electrode parts by use of low contents precious metals of rare metals) funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)+2 种基金the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(2022R1F1A1072569)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science,ICT & Future Planning(NRF2020R1C1C1010493)“Regional Innovation Strategy(RIS)” through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(MOE)(2021RIS-004)。
文摘Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.
基金supported by the National Natural Scientific Foundation of China(No.21437005)the State Hi-tech Research and Development Project of the Ministry of Science and Technology,Peoples Republic of China(No.2012AA063401)the special fund of State Key Joint Laboratory of Environmental Simulation and Pollution Control(No.15L03ESPC)
文摘Nitrogenous heterocyclic compounds are key pollutants in coking wastewater; however, the functional potential of microbial communities for biodegradation of such contaminants during biological treatment is still elusive. Herein, a high throughput functional gene array（Geo Chip 5.0）in combination with Illumina Hi Seq2500 sequencing was used to compare and characterize the microbial community functional structure in a long run（500 days） bench scale bioreactor treating coking wastewater, with a control system treating synthetic wastewater. Despite the inhibitory toxic pollutants, Geo Chip 5.0 detected almost all key functional gene（average61,940 genes） categories in the coking wastewater sludge. With higher abundance, aromatic ring cleavage dioxygenase genes including multi ring1,2 diox; one ring2,3 diox; catechol represented significant functional potential for degradation of aromatic pollutants which was further confirmed by Illumina Hi Seq2500 analysis results. Response ratio analysis revealed that three nitrogenous compound degrading genes-nbz A（nitro-aromatics）, tdn B（aniline）, and scn ABC（thiocyanate） were unique for coking wastewater treatment, which might be strong cause to increase ammonia level during the aerobic process. Additionally, Hi Seq2500 elucidated carbozole and isoquinoline degradation genes in the system. These findings expanded our understanding on functional potential of microbial communities to remove organic nitrogenous pollutants;hence it will be useful in optimization strategies for biological treatment of coking wastewater.
文摘Reaction of (MeC 5H 4) 3Ln with HOCH 2CH 2NMe 2 in tetrahydrofuran(THF) gives the new complexes [(MeC 5H 4) 2Ln(μ OCH 2CH 2NMe 2)] 2 (Ln=Sm, Y, Nd) with nitrogen functionalized μ alkoxide ligand. The complexes were characterized by elemental analysis and IR, and [(MeC 5H 4) 2Sm(μ OCH 2CH 2NMe 2)] 2 was structurally characterized by the X ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm-N bonds via intramolecular coordination of OCH 2CH 2NMe 2. The coordination number of the central metal Sm is nine. The title complexes show good catalytic activity for ring opening polymerization of ε caprolactone.
基金supported by the Liaoning Provincial Scientific Research Fund (JYTYB2024046)
文摘Background The forest-steppe ecotone,a critical transition zone sensitive to global change,faces increasing nitrogen deposition.However,the interplay between nitrogen conversion processes and soil enzyme activity remains unclear.We investigated the effects of nitrogen addition on plant nutrient dynamics,microbial functional genes,and enzyme activity in northwest Liaoning,China.Results Nitrogen addition significantly increased leaf nitrogen content in Potentilla tanacetifolia(peak under N40)and Artemisia frigida(peak under N40),while Lespedeza daurica showed a non-linear response(peak under N20).Phosphorus content remained unaffected across species.Soil enzyme activities(urease,nitrate reductase,dehydrogenase)increased with nitrogen input,with protease activity rising proportionally to nitrogen addition rate.Functional genes(nirK,nifH,AOB-amoA)exhibited dynamic responses:nirK abundance peaked under N40,nifH under N10,and AOB-amoA increased with nitrogen input.Structural equation modeling revealed that nirK gene abundance positively influenced enzyme activity(λ=0.512),while nifH negatively correlated with leaf N/P ratios(λ=-0.606).Soil protease activity directly drove leaf N/P ratios(λ=0.734).Conclusions Nitrogen addition enhances plant nitrogen uptake and enzyme-driven mineralization,but speciesspecific responses highlight ecological trade-offs.Soil pH and protease activity are pivotal in mediating nitrogen conversion and plant nutrient stoichiometry.These findings underscore the need to integrate microbial and enzymatic dynamics into nutrient management strategies for ecotones under nitrogen enrichment.
基金supported by the Innovative team project of Nanjing Institute of Environmental Sciences,MEE(GYZX200101)the National Natural Science Foundation of China(52270160,and U23A2058)+1 种基金the Key R&D Program of Ningxia Hui Autonomous Region(2021BEG01002)the Xinjiang UygurAutonomous Region Science and Technology ProgramPlan(2022E02026)the SuperG project of EUHorizon 2020 program(774124).
文摘Freshwater salinization is receiving increasing global attention due to its profound influence on nitrogen cycling in aquatic ecosystems and the accessibility of water resources.However,a comprehensive understanding of the changes in river salinization and the impacts of salinity on nitrogen cycling in arid and semi-arid regions of China is currently lacking.A meta-analysis was first conducted based on previous investigations and found an intensification in river salinization that altered hydrochemical characteristics.To further analyze the impact of salinity on nitrogen metabolism processes,we evaluated rivers with long-term salinity gradients based on in situ observations.The genes and enzymes that were inhibited generally by salinity,especially those involved in nitrogen fixation and nitrification,showed low abundances in three salinity levels.The abundance of genes and enzymes with denitrification and dissimilatory nitrate reduction to ammonium functions still maintained a high proportion,especially for denitrification genes/enzymes that were enriched under medium salinity.Denitrifying bacteria exhibited various relationships with salinity,while dissimilatory nitrate reduction to ammonium bacterium(such as Hydrogenophaga and Curvibacter carrying nirB)were more inhibited by salinity,indicating that diverse denitrifying bacteria could be used to regulate nitrogen concentration.Most genera exhibited symbiotic and mutual relationships,and the highest proportion of significant positive correlations of abundant genera was found under medium salinity.This study emphasizes the role of river salinity on environment characteristics and nitrogen transformation rules,and our results are useful for improving the availability of river water resources in arid and semi-arid regions.
文摘To improve nitrogen removal performance of wastewater treatment plants （WWTPs）, it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study characterized the quantity and diversity of nitrogen cycling genes in various processes of municipal WWTPs by employing two molecular-based methods：most probable number-polymerase chain reaction （MPN-PCR） and DNA microarray. MPN-PCR analysis revealed that gene quantities were not statistically different among processes, suggesting that conventional actwated sludge processes （CAS） are similar to nitrogen removal processes in their ability to retain an adequate population of nitrogen cycling microorganisms. Furthermore, most processes in the WWTPs that were researched shared a pattern：the nitS and the bacterial amoA genes were more abundant than the nirK and archaeal amoA genes, respectivelv. DNA microarray analysis revealed that several kinds of nitrification and denitrification genes were detected in both CAS and anaerobic-oxic processes （AO）, whereas limited genes were detected in nitrogen removal processes. Results of this study suggest that CAS maintains a diverse community of nitrogen cycling microorganisms; moreover, the microbial communities in nitrogen removal processes may be specific.
基金supported by the National Key R&D Program of China(2022YFF1300900)the National Natural Science Foundation of China(32271624)+1 种基金the Foundation of Jilin Scientifc and Technological Development Project(20220203003SF)the Education Department of Jilin Province(JJKH20230516KJ).
文摘Direct sewage discharge may enhance soil nitrous oxide(N_(2)O)emissions,worsening the greenhouse effect.However,the effects of sewage discharge into bogs on N_(2)O flux,drivers and influencing mechanisms remain unclear.Additionally,investigating the impact of reclaimed water on N_(2)O flux is important for bog replenishment and water shortage alleviation.This study simulated sewage from different sources into a bog and analyzed N_(2)O fluxes,soil(organic carbon,total nitrogen,ammonium nitrogen,nitrate nitrogen,total phosphorus,available phosphorus,pH and electrical conductivity),plant(species richness and biomass)and microorganisms(ammonia-oxidizing archaea,napA,nirS,nirK and nosZ genes).Results showed that the reclaimed water did not significantly change N_(2)O flux,while 50%tap water mixed with 50%domestic sewage and domestic sewage significantly increased the N_(2)O flux.Among soil factors,available nitrogen and pH were key in influencing N_(2)O flux.Among plant parameters,species richness was the primary factor affecting N_(2)O flux.Nitrogen transformation functional genes contributed the most to the increase in the N_(2)O fluxes,with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N_(2)O emissions.Therefore,domestic sewage should be considered,as it significantly increases N_(2)O emissions by affecting the soil,plants and microorganisms,thereby increasing the global warming potential.This study’s findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.
